As the automobile body is constructed with an approximately 0.8 mm thick steel plate, the body likely vibrates when the automobile runs. It is necessary to reduce the vibrations for keeping the inside room quite and comfortable so that different measures for vibration reduction have been developed.
For reducing the vibration, a vibration damping steel sheet comprising of a viscoelastic layer sandwiched between the steel sheet or a vibration damping sheet consisting of a viscoelastic materials, such as an asphalt mixed with some fillers being pressed to a sheet.
However, a vibration reduction efficiency of the vibration damping steel sheet is rather low and the sheet is rather heavy, subsequently the weight of the automobile increases, and the cost is high.
The vibration damping sheet made of asphalt exhibits enough vibration damping effect, but in a production line in a factory, it is difficult or impossible to install the vibration damping sheet onto the body automatically, therefore a worker should install the sheet manually, and which is costly.
To solve this problem, vibration damping paint, which is applied on a body surface like ordinary paint is developed and it exhibits an enough vibration damping effect. As the vibration damping paint can be conveniently applied on a desired part of the surface by spraying means, it is easy to provide an automatic production system. However, the vibration damping paint should be coated thick enough to exhibit enough vibration damping effect compared with a conventional heat setting paint, the heat drying process condition of the vibration damping paint is restricted and costly for performing the maximum efficiency.
But the current trend in the automobile industry is energy saving and high fuel efficiency, so it is required to form a vibration damping paint layer at low temperature and with short time drying process.
[Patent document 1] JP H07-145331 A
[Patent document 2] JP 2002-375865 A